I need just a 28 tooth cog (or 27 if no 28 can be found). I don't need the whole cassette, just the cog. Looking for a good low price and fast shipping. I need it in less than 3 weeks.

I need just a 28 tooth cog (or 27 if no 28 can be found). I don't need the whole cassette, just the cog. Looking for a good low price and fast shipping. I need it in less than 3 weeks.

The whole cassette is <$28....or call your LBS .
http://www.comparisonpricing.com/bikesource.htm
A single cog may cost $15 and add $8 for S/H ......may as well get the whole group :confused:

Why not just buy a mountain bike cassette. The XTR came in a 9 speed 28. The weight penalty wouldn't be that bad.

That's what I'm thinking about, but I don't care about the weight of the cassette. Increasing my overall mass by even a 100g wouldnt make a real difference when I'm going up the mountain with man and machine at 95kg.

Very intelligent thinking. If it isn't rotating weight it isn't critical. Most people carry more up a mountain in their spare tire pouch and water bottle than the difference between Dura-Ace and Ultegra cassettes. The XTR cassette even matches the color of Dura-Ace in the grey, so nobody else will be the wiser to boot.